A novel class of 2-amino-4-nitropyrazolo [1, 5-a] pyrimidines has been identified as potent inhibitors of coxsackievirus B3 replication. The synthesis of these compounds is based on the regioselective reaction of 3, 5-diamino-5-nitropyrazole with unsymmetrical β-diketones at catalysis by hydrochloric acid leading to 2-amino-4-nitropyrazolo [1, 5-a] pyrimidines as key steps.